R1:a56f9a1a5599

Clean up remove participant language in Conpherence

Summary: Updates the language to use "Remove Participant" instead of "Banish User"

Test Plan: Read through the various cases, test them by removing myself or others

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D17697